Alkylation of hydrocarbons



Jan. 6, 1942.

F. H. BRUNER ALKYLATION 0F HYDROCARBONS UNREAOTED ISOPARAFFIN 3" an GASOLINE so BUTANE Filed May 11, 1939 REACTION PRODUCTS 1 ABSORBER &Q/ 4' l REACTOR 2/ 04cm (LIQUID) REACTOR I ABSORBER SETTLER h ABSORBER v I SPENT ACID FRANK H. BRUN ER ATTORNEYS rem dies. s, 1942 UNITED STATES? ii PATENT oar-ICE;

mmrronor maocsaaons mamameaw.

. meme 7 New York, N. 1., a

tatoThe'IeneOom eorporationolnelaware' Application m 11, 1939, Serial n 273.072. 4

16 Claims.- This invention relates to the alkylation oi paraflin hydrocarbons with oleiin'hydrocarbom in the. presence oi,a liquid catalyse-such as sulphuric acid, to produce high anti-knock hydro-' carbons suitable for motor iuel.

The invention broadly contemplates a contin- 1 none method 0! alkylation wherein a hydrocarbon traction containing isop/ and a liquid alhlation catalyst are passed to-a reaction zone,

or to a plurality of such zones arranged in stages, through which a substantial proportion 01 the catalyst is recycled, while normally gaseousolefin hydrocarbons are continuously injected in v the recycled liquid as it returns to thereaction vzoneorsones.

The injected hydrocarbons may comprise in part normally gaseous paraflln hydrocarbons which do not enter into the reaction orare undesired. Therefore, the .invention contemplates treating the recycled liquid containing injected gaseous hydrocarbons so .asto remove these nonreactive or undesired from the system prior to returning the liquid to the reaction zone.

The alkylation catalyst comprises a liquid compound, such as concentrated, sulphuric acid. However; it is contemplated that other liquid alkylation catalysts eiiective for the purpose may be used, such as may be prepared by passing BF:

into water to complete saturation. v

More specifically the invention comprises alunabsorbed suchas propane, are

discharged irom the absorber while theliquid catalyst containing the absorbed oleiln hydrocatalyst is recycled to the same stageywhile a portion oi the withdrawn liquid may be conducted to -a succeeding reaction stage.

molecular weight hydrocarbons are passed to each 01 a number or stages, being injected in the stream or catalyst which is recycled to each One important objector the invention is the avoidance of maintaining pressures throughout the reaction stages substantially above those neaessarytomaintainthefiehydrocarbonsinthe liquid phase. in other words, by injecting the gaseous hydrocarbons, such aspropylenezinto 'astreamotrecyclingliquidcatalystitisunneckylating isoparaflin hydrocarbons with olefin hydrocarbons, inc1uding C: and C4 'oleii'mi. This suitable for is accomplished by forming a i'raction comprising paramn and oleilmhydrocarbons having not less than iour carbon'atoms in the molecule andiorming a separate traction comprising C: and lower molecular weight hy'drocarbons. This second traction thus comprises propylene, propane, and lighter hydrocarbons.

The hydrocarbon fraction comprising Cl and higher molecular weight; hydrocarbons is j subiected to contact with a liquid alkylation catalyst, such as concentrated sulphuric acid, in a reaction zone or e maintained under pressure notsubstantia v higher than that required to maintain the c. v'idrocarbo'ns in the liquid phase.- Aperition oi the used catalystis continuously withdrawn from a settler oi the reaction stage conducted'to an absorption zone. I

The cmnd lower molecular weight hydrocarbon traction in gaseous form is iniected'in the I withdrawn liquid and maintainedin contact with the. liquid during passage through an absorption zone so that the olefin hydrocarbon constituents ator2.- I v The distillate fraction, which contain substa'ntial amounts of isoparamn in k essary to employ a pressure suillciently elevated to liqueiy the Ca hydrocarbons. Another object upon reference to the rollowingdescription read f in connection with the accompanying drawing "which comprises a tical sketch oi flow practicing the process of the inven- Ahydrocarbonmixture,s'uchasanunstabilized cracked naphtha containing paramn and,.oleii n hydrocarbons suitableior alkylation is obtained fromasourcenotshownandpassedthrougha pipe i to a iractionator or stabilizer 2.. A distillate'fraction comprising C4, Cs and lighter hydrocarbons'is removed as a distillate through a pipe 3, while the resulting stabilised naphtha oi the traction-1' is of! from the bottom addition to the oleflns and. normal passed to a iractionator 4,'where the C' and lower molecular weight hydrocarbons, such as propylene, propane, ethylene, etc., are separated from the C4 and higher molecular-weight hydrocarbons that may be present;

1 The C4 fraction is drawnoil! from the bottom oi the rractionator through a pipe .6 conv I ducted to a reactor It is brought into intimate are absorbed from the gasby the The 58 contact with sulphuric ag id within Ca and lower bottom. This used acid is drawn off by means of a pump 9 and at least a substantial portion thereof is passed to a mixing coil Ill wherein it is brought into contact with the Ca and lighter hydrocarbons injected through a branch pipe ll. These gaseous hydrocarbons comprise the distillate fraction removed overhead from the fractionator through a cooling coil I2 and a pipe.

i3, communicating with branch pipe II.

The mixture from the mixing coil Ill passes to the lower portion of an absorber or absorption tower II and rises upwardly therethrough. Fresh aacaaso a pump 40 to the preceding stage or recycled to the reactor 28. V

As indicated, a portion of the used acid drawn off from the settlers in each stage may be conducted to the absorber of a succeeding stage.

, Also, as indicated, the fresh C4 hydrocarbon fraction may be introduced to a plurality of the reactors.

sulphuric acid is introduced to the upper-portion of the absorber ll through a pipe l5. The unabsorbed hydrocarbons, such as propane, are discharged from the top of the absorber ll through a pipe [8 containing a suitable relief valve to maintain the pressure within the absorber slightly higher than ,the C4 pressure in the reactor 6. The acid containing the absorbed olefln hydrocarbons overflows from the absorber ll through a pipe ii to the reactor 6, thus coming into direct contact with the C4 hydrocarbons and the recycled isoparaflin.

A portion of the used. acid drawn oil! by the the succeeding stage.

The hydrocarbon mixture accumulating in the upper portion of the. settler 8 overflows to a reactor I! of the succeeding stage and there comes into contact with the liquid mixture overflowing from the second-stage absorber I8. The overflow from reactor 19 passes to a settler 20 wherein used acid settles to the bottom. As described in connection with the preceding stage, the used acid is drawn off from the bottomof the settler 20 by a pump 2| and the desired portion thereof passed to 'a mixing coil 22 wherein it is brought into contact with a fresh gaseous hydrocarbon fraction injected from a branch pipe 23, The used acid containing the injected hydrocarbons passes upwardly through the absorber ll from the'top of which the unabsorbed hydrocarbon is discharged through a pipe 24.

Likewise, the hydrocarbon mixture flows from the upper portion of the settler 20 to a reactor 25 of a succeeding stage wherein it is brought into contact with acid and absorbed hydrocarbons overflowing from the third stage absorber 26. The liquid mixture flows from the reactor 25 to a settler 21. Used acid is drawn off from the bottom ofthe settler 21 by a pump 28 and passed through a mixing coil 22 to the absorber 26. Fresh 0: hydrocarbon fraction is introduced to the coil 2! from a branch pipe 3|.

The hydrocarbon mixture from the upper por-v tion of thesettler 33 to a reactor 38 wherein the reaction is completed. The reacted mixture passes to a settler 32. The spent ,acid

is drawn of! from the bottom of the settler 8!.

Any desiredportion, howevenmay be passed'by pump 8 may be conducted to an absorber ll of v The reaction product accumulating in the upper portion of the settler 39 is drawn oil to a neutralizing vessel 4| wherein it may be new I Y tralized by treatment with alkali. The neutralized product is drawn on through a pipe 42 to a stabilizer 43. In thestabilizer A3 the unreacted isoparaflln, i. e., isobutane, is removed-overhead through a condenser 44 and returned through pipe 45, preferably to the first stage reactor 8.'

Additional isobutane may be required, in'which case the makeup is added from a source not shown through a pipe 46. I 1

If desired, a separatedistillate fraction com.- prising normal butane maybe removed as a side stream from the stabilizer 43 through a cooler 41. The higher-boiling hydrocarbons are drawn 01! from they bottom of the stabilizer l2 and passed through a pipe 48 to a fractionator 49.

The fractionation in the fractionator .40 is controlled so as to produce a distillate fraction having a boiling range suitable for motor fuel or aviation gasoline; for example, the distillate may have an end boiling point of 311 F. to produce an aviation gasoline. The higher boilinghy'drocarbons are drawn off from the bottom of the fractionator 49.

The sulphuric acid used as a catalystis concentrated acid of about 88 to 100% H2804, and preferably of about 94 to 98% strength.

The temperature of reaction maintained in each stage may range from about 40 to125 .and preferably about to F. with a time of reaction from about 10 to minutes and preferably about 20 to 60 minutes.

It is desirableto maintain an excess of isobutane in each reactor, for example, a ratio-of isoparamn to oleflns of between about 3:1 and 5:1 or over. Lower ratios may be employed but usually in excess of 1:1.

The temperatures maintained in the absorbers may be approximately the same as those prevailing in the reaction'zones, i. e., around 60 to 80 1 While in describing the drawing reference has been made to a single hydrocarbon source for the Ca and C4 hydrocarbons, it is contemplated that the C4 and C; fractions may be derived from different sources. The C: gaseous fraction may comprise substantially purepropylene or a gas consisting primarily of propylene.

Obviously many modiflcations and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and therefore only. such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A process for 'alkylating isoparaflin hydrocarbons with oiefln hydrocarbons, including C4 and C: oleflns, which comprises subjecting a hydrocarbon fraction comprising oleflns and par,-

aflins having four and more carbon atoms per molecule, to'contact with a liquid alkylatio'n catalyst in the presence of an isoparaflin hydrocarbon in a reaction stage maintained under pressure sufficient to maintain Cr hydrocarbons in the liquid phase, continuously-withdrawing a stream of used catalyst from the reaction stage,

carbon traction comprising olefins and nonolefinssuchthatolefinsareabeorbedandnon- -oiefins rejected, removing the rejected hydrocarbons, and returning the stream containing absorbed olefins to the rmtion stage.

2. The methodaccording to claim 1 in which. the alkylation catalyst comprises concentrated sulphuric acid.

3. ii process for alkylatin'g isoparafiin hydrocarbons with olefin hydrocarbons, including 04 and Ca olefins, the C: olefins being associated with other low molecular weight hydrocarbons. including propane; which comprises subjecting paraifin andolefin hydrocarbons, having not less than four carbon atoms inthe molecule, to contact with a liquid alkylation catalyst in the presence oian isoparafiln hydrocarbon in a reaction stage maintained under pressure not substantially higher than required to maintain C6 117- drocarbons in the liquid phase, continuously withdrawing a stream 01 used catalyst from the reac-' tion stage, injecting Cs olefin and associated hydrocarbons in said stream. passing the stream and injected hydrocarbons through an absorp- :5

tion zone wherein olefin constituents oi the injected hydrocarbons areabsorbedand other constituents rejected-removing the rejected constituents and returning the liquid containing absorbed hydrocarbons to the reaction stage.

4. The method according to claim 3 in which the reaction catalyst comprises concentrated sulphuric acid. 1 v

5. A method of alkylating' isoparafiins with olefin hydrocarbons including and C4 olefins, the

C: olefins being associated with other iow-boiling hydrocarbons, including propane, in the presence ot a liquid alkylation catalyst, which comprises passing a hydrocarbon fraction containing 3 isoparafilns and. C4 olefins through a series of reaction stages in contact with said catalyst, continuously withdrawing used catalyst from each 7 reaction stage, continuously and separately conducting catalyst withdrawn i'rom ,a plurality of said reaction stages through separate absorption zones, introducing Cs olefin and associated hydrocarbons to each of saidabsorption zones, absorbing olefin hydrocarbons in the catalyst passing through said absorption zones, discharging unabsorbedwhydrocarbons from the absorbers. and

returning said catalyst containing absorbed olefins to the reaction stage from which it was withdrawn.

6. The method according to claim in which the catalyst comprises concentrated sulphuric 7. The method according to claim 5 in which a high ratio of isoparafiln to olefin is maintained in each stage. I 8. A method or alkylation or isoparafiins with olefins including normallygaseous olefin hydroseparately conducting catalyst withdrawn from a plurallty oi said reaction stages through separate absorption zones,- introducing a' us hydrocarbon fraction containing olefins and turated hydrocarbons to each of said absorption zones, absorbing olefin hydrocarbonsdn the catalyst passing through said absorption sones. disaction zone; I I o charg g unabsorbed hydrocarbons rrom the ab- 14:. The method according to claim 13 in whichaseaaso i 3 .iniectinginsaidstreamaCsandlighterhydro-' sorptionsoneareturningsaidcatalntcontaining absorbedolefinstothereactlonstagenom-which' it waswithdrawn'. and passing a portionoi the catalyst withdrawniromaprecedingstagetothe abeorpflonsoneoiasucceedingstage 9. Acontinuousprocess ioralkylating isoparai- .fin hydrocarbomwith clefinhydrocarbons. ih-.

'cluding C4 and C: olefins and'parafllns. which comprises subjecting a hydrocarbon fraction hydroc rbon in a reaction none, continuously withdrawing a' porticnot used'cata- 1g lystirom' the reaction zone, continuously inject-* ing a hydrocarbon traction containing mainly olefin andparaifinhydr'ocarbonshavmglessthan iour carbon atoms per molecule in the withdrawn catalyst such that olefin hydrocarbons are abggsorbedinthe withdrawn catalystandparafiin" hy'drocarbons are not absorbed, removing'the unabsorbed hydrocarbons and returning withdrawn catalyst containing absorbed hydrocarbons to the reaction zone.

- sulphuric acid. 11. A method oi alkyiating isoparafiln hydroalkylation catalyst which comprises passing a hydrocarbon traction comprising paraflin and olefin hydrocarbons having four and more carbon atomspermoleculeto aseriesorreactioncham 'bers arranged so that treated rrom each preceding chamber pass to the next suc-- ceeding chamber, subjecting the hydrocarbons in intimate contact with the catalyst in said chambersinthe presenceotanisoparafiinhydroear I 40 bon, continuously and separately withdrawing streams'oi used catalyst from a plurality of chambers, continuously injecting a hydrocarbon traction containing'mainly olefin and hydrocarbons having less than four carbon atoms per molecule in said streams such that olefin hydrocarbons are absorbed in the streams and parafiln hydrocarbons are not absorbed, removing the unabsorbed hydrocarbons and returning said streams containing absorbed hydrocarbons to the reaction chambers from which withdrawn. 7 I

' 12. The method according to claim-11 in which thecatalyst is concentrated sulphuric acid.

13. In a process for allrylating isoparafiln hydrocarbons with olefin hydrocarbons, including Cl and. C: olefins, the steps comprising .io'rming a hydrocarbon fraction containing parafi'in and olefin hydrocarbons having four and more carbon atoms per molecule and a separate hydrocarbon fraction containing mainly olefin and parafiin hydrocarbons having less than four carbon atoms per molecule, subjecting the first-mentioned fraction to contact with a liquid alkylation catalyst in a zone of reaction in the presence of an isoparafiln hydrocarbon, continuously withdrawing a portion of used catalyst from said none, subjecting the withdrawn catalyst to'. contact with 7 'said separate and more volatile hydrocarbon traction, selectively absorbing olefins from said separateiraction in the withdrawn catalyst, reject- 7 'ing the unabsorbed hydrocarbons from said sellarate traction, and returning the withdrawn catalyst containingabsorbed hydrocarbons to the rem. The method according to claim on which the alkylation catalyst comprises concentrated.

carbons in the presence of a ,liquid alkylation catalyst which comprises passing a hydrocarbon fraction containing isoparamns through a series of reaction stages in contact with said catalyst,

continuously and separately withdrawing streams comprising used catalyst from a plurality of said .10

reaction stages, conducting the withdrawn streams through separate absorption'zones. introducing a hydrocarbon fraction comprising mainly normally gaseous olefln and paraflin hydrocarbons to each of said absorption zones, absorbing olefin hydrocarbons in the catalyst streams passing through said absorption zones, discharging unabsorbed hydrocarbons from the absorption zones, and continuously returning said catalyst streams containing absorbed oleiins to the reaction stages. v

16. The method according to claim 15 in which each" returning catalyst stream containing ab-- sorbed oleflns is returned to the same stage from which withdrawn.

" FRANK H. BRUNER. 

